Cambridge, MA. We are getting deep into the short season of Advent, and the words of Isaiah echo still more strongly before our mind's eye. 
On December 1, we heard this promise:
He shall judge between the nations, and shall arbitrate for many peoples;
they shall beat their swords into plowshares, and their spears into pruning hooks;
nation shall not lift up sword against nation, neither shall they learn war any more. (Isaiah 2)
And today, the Second Sunday of Advent, we heard that promise extended to all of nature, living beings changed deep down, learning to live in peace:
Then the wolf shall be a guest of the lamb, and the leopard shall lie down with the kid;
the calf and the young lion shall browse together, with a little child to guide them.
The cow and the bear shall be neighbors, together their young shall rest; the lion shall eat hay like the ox.
The baby shall play by the cobra's den, and the child lay his hand on the adder's lair.
There shall be no harm or ruin on all my holy mountain; for the earth shall be filled with knowledge of the Lord, as water covers the sea. (Isaiah 11)
Of course, we ought to watch and wait for this promised messiah, who will make all things different and new. We know we cannot create the peaceable kingdom ourselves; we cannot even change ourselves, much less the world around us. But like generations of the Jewish people, we wait in hope, waiting for God to aid us now and in the future in times of trouble; we wait for God to make all things right. Hence this lovely winter season of watching in hope.
But this waiting is not passive. It really works only when the waiting itself seeps inside us and actually changes us deep down. This is where today’s Gospel comes into play. John the Baptist is introduced in Luke’s Gospel as the cousin of Jesus, but here in Matthew 3 he simply appears. He comes out of the desert unexplained, unexpected, and most oddly:
In those days John the Baptist appeared in the wilderness of Judea, proclaiming, “Repent, for the kingdom of heaven has come near.” …Now John wore clothing of camel’s hair with a leather belt around his waist, and his food was locusts and wild honey.
I of course have no inside information on this, but my imagination went to work in today’s Sunday morning homily: John too must have meditated on Isaiah 2 and Isaiah 11; he too must have yearned for a better, more peaceable Israel. But he must also have realized that for these words to become true, people like him had to change even now, right now: the path has to be cleared. And so he fled to the desert, he lived among wild beasts — for months, for years? — he dressed in animal skins and lived off the land: he cleared a path right through his own body and mind and heart, that this small way be ready for the Lord. He was speaking of himself too when he cried out still other words from Isaiah:
The voice of one crying out in the wilderness: ‘Prepare the way of the Lord, make his paths straight.’
When John then preached to the people to change their lives and repent, he was only asking of them what he had first demanded of himself. Indeed, he was credible because he preached only what he practiced, and his words had effect only because they had been cleansed of ego and the easy comforts of ordinary life:
Then the people of Jerusalem and all Judea were going out to him, and all the region along the Jordan, and they were baptized by him in the river Jordan, confessing their sins.
Advent today, our clearing of a path through ourselves as individuals and as community: this is a beautiful idea. But even as John spoke and crowds came to him, inevitably there were those who found it to be a frightening message, this notion of waiting as a purification, a demand to change even before God arrives. Some, it seems, were content to wait for the coming of God, but only on their own terms, unchanged at the present moment. And so it was that John turned in anger on those who came as spectators, expecting to return home exactly as they had come:
You brood of vipers! Who warned you to flee from the wrath to come? …Even now the ax is lying at the root of the trees; every tree therefore that does not bear good fruit is cut down and thrown into the fire… One who is more powerful than I is coming after me; I am not worthy to carry his sandals. He will baptize you with the Holy Spirit and fire. His winnowing fork is in his hand, and he will clear his threshing floor and will gather his wheat into the granary; but the chaff he will burn with unquenchable fire.
But the changing continues, because it is unpredictable. The chapter ends with a short passage we did not hear in church this morning, but which makes this final point. John, waiting, meditating, purified and purifying, still had in mind what the Messiah would be like, and so he was still able to be deeply surprised:
Then Jesus came from Galilee to John at the Jordan, to be baptized by him. John would have prevented him, saying, “I need to be baptized by you, and do you come to me?” But Jesus answered him, “Let it be so now; for it is proper for us in this way to fulfill all righteousness.”
The long awaited one did not come by breaking open the heavens; God did not come out of the desert, nor wielding the sword of justice or the fiery torch of purification. Jesus simply walked up, along with and amid the crowd, and asked to be baptized. For the moment, he was just one more of God’s people joining in the communal purification at the desert's edge. John was pure enough in his heart to stop looking to the desert or the skies, and to recognize the person standing there right in front of him.
Our final surprise too in the Advent season may be that God does come, even in 2019, but most often in smaller and quieter ways than we had expected: just one sword becomes a plowshare, just one wolf lies down with a lamb, just one lion becomes vegetarian, and just one child plays with one viper who is no longer deadly: just one visit by Jesus for each of us, the change in the world beginning one heart at a time.
(Based on a homily for the second Sunday of Advent; but, for another context, the theme is rich in interreligious implications, regarding the waiting and practices of waiting; what is or can be hoped for; how obstacles, particularly lack of holy imagination, are faced; and what might constitute in various traditions a surprise akin to Jesus just "showing up" in the crowd by the river.)
